Limit number of files per pages site

Remove pages_limit_entries_count feature flag

It's tested in prod and enabled for everyone

Changelog: added

app/services/projects/update_pages_service.rb

@@ -294,8 +294,6 @@ module Projects
     end
 
     def pages_file_entries_limit
-      return 0 unless Feature.enabled?(:pages_limit_entries_count, project, default_enabled: :yaml)
-
       project.actual_limits.pages_file_entries
     end
   end

config/feature_flags/development/pages_limit_entries_count.yml

----
-name: pages_limit_entries_count
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/64925/diffs
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/334765
-milestone: '14.1'
-type: development
-group: group::release
-default_enabled: false

spec/services/projects/update_pages_service_spec.rb

@@ -156,13 +156,6 @@ RSpec.describe Projects::UpdatePagesService do
         expect(GenericCommitStatus.last.description).to eq("pages site contains 3 file entries, while limit is set to 2")
       end
 
-      it 'does not limit pages file count if feature is disabled' do
-        stub_feature_flags(pages_limit_entries_count: false)
-        create(:plan_limits, :default_plan, pages_file_entries: 2)
-
-        expect(execute).to eq(:success)
-      end
-
       it 'removes pages after destroy' do
         expect(PagesWorker).to receive(:perform_in)
         expect(project.pages_deployed?).to be_falsey